Damage Analysis of Freeze-Thaw Processes in Hydraulic Structure Concrete

2012 ◽  
Vol 446-449 ◽  
pp. 2681-2684
Author(s):  
Ya Qi Gong ◽  
Jian Hua Cui ◽  
Hai Dong Su ◽  
Liang Shan
Keyword(s):  
Load Capacity ◽  
Water Pressure ◽  
Damage Evolution Equation ◽  
Freeze Thaw ◽  
Hydraulic Concrete ◽  
Gravity Load ◽  
Deterioration Process ◽  
Design Loads ◽  
Thaw Zone ◽  
Theory Of Damage

Based on the theory of damage finite element method, the deterioration process of hydraulic concrete under the freeze-thaw cycles is simulated. The damage evolution equation is deduced and freeze-thaw zone is discussed. The results indicate that the load capacity of structure is degraded under the freeze-thaw cycles. The deterioration of hydraulic concrete under the freeze-thaw cycles, however, is mainly limited at the region of the water fluctuation district and has a little effect to the overall structure. This means that the major loads causing hydraulic concrete failure under the freezing-thawing damage in the coldest region is not those of general design loads, such as gravity load and water pressure load, but the thermal loads, especially by the distinct daily temperature difference. Thus, the freeze-thaw modeling should consider these loads together.

Effect of Saturation Degree on Concrete Deterioration due to Freeze-Thaw Action

2011 ◽  
Vol 477 ◽  
pp. 404-408 ◽  
Author(s):  
Wen Cui Yang ◽  
Yong Ge ◽  
Bao Sheng Zhang ◽  
Jie Yuan
Keyword(s):  
Frost Resistance ◽  
Water Pressure ◽  
High Water ◽  
Frost Damage ◽  
Critical Value ◽  
Cold Weather ◽  
Saturation Degree ◽  
Freeze Thaw ◽  
Air Content ◽  
The Difference

Freezing-thawing durability of cement concrete is extremely important in cold weather, to better understand mechanism of frost damage and air-entraining，saturation degree of pores in concrete and its relation with frost resistance were studied in this paper. Concrete specimens with different saturation degree from 0 to 100% were prepared used a sealed tin with a high water pressure pump. Then these specimens were subjected to six freezing-thawing cycles and the relative dynamic modulus of elasticity was examined. The results showed that critical saturation degree of concrete with water- binder ratio of 0.30 and 0.47, air content of 1%, 4% and 6% were from 0.60 to 0.80. When its saturation degree exceeded the critical value, concrete was deteriorated significantly after only six freeze-thaw cycles. The critical saturation degree was mainly related to the air content of concrete mixture, and it decreased with the increasing of air content. The difference between the saturation degree and the critical value can be used to evaluate potential frost resistance of concrete, and its result was consistent with the result of frost tests very well.

Damage Analysis of Concrete Subjected to Freeze-Thaw Cycles and Chloride Ion Erosion

2011 ◽  
Vol 488-489 ◽  
pp. 464-467
Author(s):  
Ji Ze Mao ◽  
Zhi Yuan Zhang ◽  
Zong Min Liu ◽  
Chao Sun
Keyword(s):  
Constitutive Equation ◽  
Evolution Equation ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Chloride Ion ◽  
Offshore Structures ◽  
Damage Evolution Equation ◽  
Freeze Thaw ◽  
Concrete Materials ◽  
Ion Erosion

With the development of damage mechanics, many researchers have used it to analyze the constitutive equation of concrete. Since the special environment in the cold marine regions, the offshore structures are common to subject to the comprehensive effects of freeze-thaw action and chloride erosion. This might cause concrete materials degradation and reduce the mechanical performance of concrete seriously. In this paper, based on the analysis and mechanical experiments of concrete materials under the comprehensive effects of freeze-thaw action and chloride ion erosion, the damage evolution equation of concrete elastic modulus along with the freeze-thaw cycles and chloride ion contents was established. The effects of chloride ion were investigated during the process of concrete degradation. According to the damage evolution equation, a new constitutive equation of concrete under freeze-thaw action and chloride erosion was established. And then, by means of the element simulation analysis of concrete beams when subjected to the comprehensive actions, the feasibility and applicability of the equation was examined and discussed. In this equation, both the freeze-thaw action and chloride ion erosion were considered together. It will be more suitable for analyzing the durability of concrete structures in the real cold marine regions. It will also provide some references for concrete constitutive theory.

Experimental Study on Seismic Performance of RC Composite Core Walls with Steel Tube-Reinforced Concrete Columns and Concealed Steel Trusses under Eccentric Horizontal Loading

2010 ◽  
Vol 163-167 ◽  
pp. 2267-2273 ◽  
Author(s):  
Hong Ying Dong ◽  
Wan Lin Cao ◽  
Jian Wei Zhang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Load Capacity ◽  
Concrete Columns ◽  
Steel Tube ◽  
Reinforced Concrete Columns ◽  
Deterioration Process ◽  
Combined Action ◽  
Process Energy ◽  
Steel Trusses

Two 1/6 scale core walls, including one RC core wall with steel tube-reinforced concrete columns and concealed steel trusses and one conventional RC core wall, were tested under eccentric horizontal cyclic loading. The load-capacity, ductility, hysteresis characteristics, stiffness, stiffness deterioration process, energy dissipation and damage characteristics of the two specimens were compared and discussed in this paper. It shows that the seismic performance of the RC core walls under combined action could be improved by setting the concealed steel trusses in the walls and using the steel tube-reinforced concrete columns as the boundary elements.

scholarly journals Influence of Water Pressure on the Mechanical Properties of Concrete after Freeze-Thaw Attack under Dynamic Triaxial Compression State

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Ruijun Wang ◽  
Yan Li ◽  
Yang Li ◽  
Fan Xu ◽  
Xiaotong Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Water Pressure ◽  
Mass Loss Rate ◽  
Triaxial Compression ◽  
Ultimate Compressive Strength ◽  
Peak Strain ◽  
Freeze Thaw ◽  
Dynamic Triaxial Compression

This study aims at determining the effect of water pressure on the mechanical properties of concrete subjected to freeze-thaw (F-T) attack under the dynamic triaxial compression state. Two specimens were used: (1) a 100 mm × 100 mm × 400 mm prism for testing the loss of mass and relative dynamic modulus of elasticity (RDME) after F-T cycles and (2) cylinders with a diameter of 100 mm and a height of 200 mm for testing the dynamic mechanical properties of concrete. Strain rates ranged from 10−5·s−1 to 10−3·s−1, and F-T cycles ranged from 0 to 100. Three levels of water pressure (0, 5, and 10 MPa) were applied to concrete. Results showed that as the number of F-T cycles increased, the mass loss rate of the concrete specimen initially decreased and then increased, but the RDME decreased. Under 5 MPa of water pressure and at the same strain rate, the ultimate compressive strength decreased, whereas the peak strain increased with the increase in the number of F-T cycles. This result is contrary to the variation law of ultimate compressive strength and peak strain with the increase in strain rate under the same number of F-T times. With the increase in F-T cycles or water pressure, the strain sensitivity of the dynamic increase factor of ultimate compressive strength and peak strain decreased, respectively. After 100 F-T cycles, the dynamic compressive strength under all water pressure levels tended to increase as the strain rate increased, whereas the peak strain decreased gradually.

Temporal rainfall patterns with water partitioning impacts on maize yield in a freeze–thaw zone

2013 ◽  
Vol 486 ◽  
pp. 412-419 ◽  
Author(s):  
Fanghua Hao ◽  
Siyang Chen ◽  
Wei Ouyang ◽  
Yushu Shan ◽  
Shasha Qi
Keyword(s):  
Maize Yield ◽  
Freeze Thaw ◽  
Water Partitioning ◽  
Thaw Zone ◽  
Rainfall Patterns

scholarly journals Fracture mechanism of rock collapse in the freeze-thaw zone of eastern Sichuan-Tibet Mountains under seasonal fluctuating combinations of water and heat

2021 ◽  
Author(s):  
Yong Wu ◽  
Xinpo Li ◽  
Lei Zhu
Keyword(s):  
Hydrostatic Pressure ◽  
Fracture Mechanics ◽  
Freezing Stress ◽  
Collapse Mechanism ◽  
Water Ice ◽  
Freeze Thaw ◽  
Different Seasons ◽  
Rock Collapse ◽  
Thaw Zone ◽  
Eastern Sichuan

Abstract In the freeze-thaw zone of eastern Sichuan-Tibet Mountains, the phases of water in cracks show strong seasonal variations, which significantly affect the stability of perilous rocks in mountains. However, few works have clearly addressed the role of water/ice in crack development from a fracture mechanics viewpoint to explain the seasonality of rock collapse. In this study, we built physical models from a fracture mechanics viewpoint to calculate water-freezing stress, hydrostatic pressure, and their combinations induced by water/ice in cracks, and show the crack propagation mechanism under temperature fluctuations in different seasons in mountainous regions. Based on the models, we calculate fracture conditions, simulate the crack process, and illustrate the rock collapse mechanism in different seasons by the extended finite element method. The results indicate that different phases of water, which induce stress under spatiotemporal fluctuations of temperature, determine the various propagation styles and influence what kind and when a collapse will occur. The collapse of fractured rocks in different seasons generally results from rock damage accumulation owing to the initiation, propagation, and connection of primary cracks under freezing stress or hydrostatic pressure or their different combinations.

Deformation of a concrete matrix subject to a cyclic freeze–thaw process

RSC Advances ◽  
2016 ◽  
Vol 6 (63) ◽  
pp. 58417-58425 ◽  
Author(s):  
P. Du ◽  
Y. Yao ◽  
L. Wang ◽  
D. Y. Xu ◽  
Z. H. Zhou ◽  
...  
Keyword(s):  
Residual Strain ◽  
Hysteretic Loop ◽  
Freeze Thaw ◽  
Deterioration Process ◽  
Concrete Matrix ◽  
Matrix Subject

With cyclic freeze–thaw process, the strain hysteretic loop of concrete matrix is raised upwards indicating that residual strain occurs, which proves that the damage is continuously accumulated and an irreversible deterioration process is generated.

Influence of Permeated Crystalline Materials on Durability of Hydraulic Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 1522-1527
Author(s):  
Ke Liang Wang ◽  
Ting Zheng Hu ◽  
Ling Liu
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Transition Zone ◽  
Test Methods ◽  
Sulfate Attack ◽  
Interfacial Transition Zone ◽  
Crystalline Materials ◽  
Freeze Thaw ◽  
Hydraulic Concrete

Influence of permeated crystalline materials on durability of hydraulic concrete was studied by impermeability test methods after sulfate attack and freeze-thaw cycling. Microstructure of concrete was analyzed and characterized with SEM and MIP. The results showed that impermeability pressure of concrete with permeated crystalline materials was more than that of standard concrete after sulfate attack and freeze-thaw cycling. Permeated crystalline materials improved on performance of concrete for sulfate attack and freeze-thaw, because that microstructure of interfacial transition zone of concrete with permeated crystalline materials was compact and its pore size distribution was more than that of standard concrete. There were more content of less harmful pore with diameter 20nm~100nm and less content of harmful pore with diameter100nm~200nm and more than 200nm in concrete with permeated crystalline materials than in standard concrete.

Continued Performance and Economic Issues for the Polk County Minnesota Bituminous County Road Constructed With Municipal Solid Waste Combustor Ash

2003 ◽  
Author(s):  
Samuel P. Lucido ◽  
Willard Wilson
Keyword(s):  
Load Capacity ◽  
The United States ◽  
Structural Testing ◽  
Environmental Testing ◽  
Freeze Thaw ◽  
Economic Issues ◽  
Polk County ◽  
Capacity Improvement ◽  
Bituminous Pavements

This paper is a follow up to previous installments presenting environmental, construction, performance and economic issues associated with Polk County CSAH 13. The CSAH 13 project was a demonstration of the use of municipal waste combustor (MWC) ash in bituminous. New structural and cost data is presented. The incorporation of MWC ash into bituminous pavements has been investigated in the United States since the middle 1970s. Thus far, most, if not all of these projects, have attempted to answer the questions: Is it safe? Is it feasible? Or does it provide an acceptable product? The presented project answers these questions on a new level. MWC ash amended bituminous was used to construct a portion of 2.25 miles of road in Northwest Minnesota. Significant environmental and structural testing was performed prior to, during and after construction. Environmental testing on this project has shown that the use of MWC ash in bituminous pavement, as performed, is safe. In addition, economic analysis shows important financial advantages by using ash-amended bituminous. Structural testing showed a 36% increase in stability, 19% increase in flow and a 17% increase in spring season axle load capacity. Improvement in resistance to freeze-thaw cracking was also shown.

scholarly journals Ageing deformation of tailings dams in seasonally frozen soil areas under freeze-thaw cycles

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jiaxu Jin ◽  
Shiwang Li ◽  
Chenguang Song ◽  
Xinlei Zhang ◽  
Xiangfeng Lv
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Frozen Soil ◽  
Practical Significance ◽  
Permafrost Region ◽  
Tailings Dam ◽  
Freeze Thaw ◽  
Tailings Dams ◽  
Thaw Cycle

Abstract The freeze-thaw cycle is one of the important factors in inducing a dam-break in the permafrost region, so it is of great practical significance to study the mechanism of the failure deformation of tailings dams under freeze-thaw cycles. In this paper, the water-heat-force coupling model of a tailings dam considering frost-thaw damage is established, and the freeze-thaw cyclic ageing deformation of a tailings dam in a seasonally frozen soil area is studied. The correctness of the model is validated by numerical calculation. The research shows under the same water content, the compressive strength and modulus of deformation decrease with an increase in the number of freeze-thaw cycles, the cohesion and internal friction angle decrease, and the amplitude gradually decreases before becoming stable. In the process of cooling, the pore water pressure first increases and then decreases, and the pore water pressure first decreases and then increases during the heating process. The research results can provide a theoretical basis and reference values for the stability analysis of tailings dams in seasonally frozen soil areas.

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